CVE-2012-3483 in Tunnelblick
Summary
by MITRE
Race condition in the runScript function in Tunnelblick 3.3beta20 and earlier allows local users to gain privileges by replacing a script file.
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Analysis
by VulDB Data Team • 12/15/2024
The vulnerability described in CVE-2012-3483 represents a critical race condition flaw within the Tunnelblick VPN client software version 3.3beta20 and earlier. This issue specifically affects the runScript function which is responsible for executing various scripts during the VPN connection process. The race condition occurs when the application fails to properly validate or secure script file operations, creating a window of opportunity for malicious local users to exploit the system. The vulnerability stems from the improper handling of file replacement operations during script execution, where the system does not adequately verify the integrity or authenticity of script files before execution.
The technical implementation of this flaw involves a timing-based attack vector where an attacker can manipulate the system by replacing a legitimate script file with a malicious one while the application is in the process of executing it. This race condition typically occurs when the application first checks for the existence of a script file and then proceeds to execute it without revalidating the file's state between these operations. The flaw allows for privilege escalation because the script execution context in Tunnelblick operates with elevated privileges, meaning that any malicious code executed through this vulnerability would run with administrator-level permissions. This represents a classic race condition vulnerability that falls under CWE-367, which specifically addresses time-of-check to time-of-use vulnerabilities.
The operational impact of this vulnerability extends beyond simple local privilege escalation as it provides attackers with a pathway to execute arbitrary code with elevated privileges on systems running affected versions of Tunnelblick. This could lead to complete system compromise, data exfiltration, or the installation of persistent backdoors. The vulnerability is particularly concerning in enterprise environments where VPN clients are widely deployed, as it could allow attackers to gain unauthorized access to corporate networks through a single compromised endpoint. The attack requires local access to the system but does not need network connectivity to the target machine, making it particularly stealthy and difficult to detect through traditional network monitoring approaches.
Mitigation strategies for CVE-2012-3483 should focus on immediate software updates to versions that have patched the race condition vulnerability. Users and administrators should prioritize upgrading to the latest stable release of Tunnelblick that addresses this specific issue. Additionally, implementing proper file permission controls and monitoring for unauthorized script file modifications can provide additional layers of defense. The vulnerability demonstrates the importance of proper file validation and atomic operations in security-critical applications, aligning with ATT&CK technique T1059.007 for scripting and T1068 for local privilege escalation. Organizations should also consider implementing application whitelisting policies to prevent unauthorized script execution, particularly in environments where VPN clients are deployed. The incident highlights the necessity of thorough security testing for race condition vulnerabilities, especially in applications that handle sensitive operations with elevated privileges.